/Engine/Source/Runtime/Engine/Public/SceneView.h
The renderer reserves the right to delete and replace the view family's screen percentage interface for testing purposes with the r.Test.OverrideScreenPercentageInterface CVar.
void SetScreenPercentageInterface ( [ISceneViewFamilyScreenPercentage](API\Runtime\Engine\ISceneViewFamilyScreenPercentage) * InScreenPercentageInterface )